The specific aims of the proposed workshop is to bring together for two and one half days of investigators expert in embryology, physiology, biochemistry and perinatology as well as endocrinology to discuss recent advances in fetal lung development. The exciting findings being made daily concerning the function of the factors (peptides) elaborated by the paracrine cell system which may explain how the 40 plus cells of the fetal lung function as a unfied organ which develops in very integrated fashion to produce surfactant and the structural integrity to allow normal breathing at birth (i.e. cell-cell recognition factors), need to be presented and discussed by such a group of inter-disciplinary scientists. In addition the paracrine cell system also elaborates peptides whose function are now being uncovered and which also will give rise to a fruitful discussion. Another area of great concern is beta-adrenergic and alpha-adrenergic agonists, their binding to specific receptors in the fetal lung and their function as integrators, second messengers or primary stimulants of fetal lung development. In addition we plan to discuss the function of vitamin A in fetal lung development. The proceedings of the workshop will be published as a supplement of the American Journal of Pediatrics. A total of 38,000 copies will be printed and circulated. The cost of all this will be approximately $35,000.